Field of the Invention
The present invention relates to a semiconductor device and a method for manufacturing the same, and more particularly to a power semiconductor device to be used in an inverter circuit for controlling a motor in an electric car or a train, a regenerative converter circuit, or in a booster circuit and a method for manufacturing the same.
Description of the Background Art
According to a conventional power semiconductor device, a wiring terminal to be bonded to an electrode provided on an upper surface of a semiconductor element is fixed to a resin case by integral molding (refer to Japanese Patent Application Laid-Open No. 2013-62405). Therefore, to improve precision in distance between the semiconductor element and the wiring terminal is important in assembling (manufacturing) the semiconductor device.
According to the above semiconductor device, warpage or waviness is generated in a bonded surface between the resin case and a substrate on which the resin case is arranged, due to shrinkage of a resin of the resin case. Furthermore, warpage is generated in the substrate because materials having different thermal expansion rates are bonded in a step of manufacturing the semiconductor device. Still furthermore, a bonding agent for bonding the resin case to the substrate varies in thickness.
As measures for the above problems, conventionally, a dimension of the resin case has been strictly controlled, and precision in assembling the semiconductor device has been controlled and inspected, to bond the semiconductor element to the wiring terminal within a desired distance range.
In a case where a distance is small between the semiconductor element and the wiring terminal in the conventional semiconductor device, a thermal stress applied to the semiconductor element is increased due to a thermal cycle, so that the problem is that reliability of the semiconductor device is reduced. Meanwhile, in a case where the distance is large between the semiconductor element and the wiring terminal, a brazing material such as a solder supplied to bond the semiconductor element to the wiring terminal becomes insufficient, which causes defective bonding.